Polyester blends with improved oxygen scavenging ability

ABSTRACT

Disclosed herein is an oxygen scavenging composition for containers. The oxygen scavenging composition may comprise at least one polyester component, which is a copolyester containing a metal sulfonate salt group, a transition metal catalyst, and a vegetable oil. The vegetable oil may comprise at least one molecule having a double allylic structure. The copolyester containing a metal sulfonate salt group may comprise at least one acid unit and at least one diol unit. The concentration of the double allylic structures of the vegetable oil in the composition may be greater than 5.0 meq/kg of all of the polyester components. The composition may also be void of or substantially void of a polyamide.

CROSS REFERENCES AND PRIORITIES

This application claims priority from U.S. Provisional Application No.62/174,593 filed on 12 Jun. 2015, U.S. Provisional Application No.62/174,603 filed on 12 Jun. 2015, U.S. Provisional Application No.62/174,631 filed on 12 Jun. 2015, and U.S. Provisional Application No.62/180,861 filed on 17 Jun. 2015 the teachings of each of which areincorporated herein by reference in their entirety.

BACKGROUND

U.S. Pat. No. 7,919,159 B2 to Liu et al. (“Liu”) discloses a compositionof a polyester, a partially aromatic polyamide, a cobalt salt and anionic compatibilizer that is a copolyester containing a metal sulfonatesalt. Liu teaches that the use of a transition metal catalyst to promoteoxygen scavenging in polyamide containers is well known. Liu furtherteaches that blends of an ionic compatibilizer (copolyester containing ametal sulfonate salt) and a cobalt salt results in a container havingimproved gas barrier properties, improved haze and reduced yellowness.Liu also teaches that blends of polyesters and polyamides suffer fromissues of haze and yellowness.

U.S. Pat. No. 8,871,846 B2 to Fava (“Fava”) discloses a composition of apolyester, a polyamide, a transition metal catalyst and an inert organiccompound selected from the group consisting of paraffins, vegetableoils, polyalkylene glycols, esters of polyols, alkoxylates, and mixturesof these substances with linseed oils being an example of such avegetable oil. Fava discloses that the use of an inert organic compound,which preferably is liquid at ambient temperature, in transitionmetal-based polyester/polyamide compositions for the forming ofarticles, e.g. packaging materials for personal care, medicalpharmaceutical, household, industrial, food and beverage plasticproducts, shows a considerable improvement of the oxygen scavengingperformance and a considerable reduction or a complete elimination ofthe oxygen scavenging induction period compared with known transitionmetal-based polyester/polyamide blends not comprising an inert liquidorganic compound.

SUMMARY

Disclosed herein is an oxygen scavenging composition for containerswhich may comprise: at least one polyester component which may be acopolyester containing a metal sulfonate salt group, a transition metalcatalyst, and a vegetable oil comprising at least one molecule having adouble allylic structure, wherein the copolyester containing a metalsulfonate salt group may comprise at least one acid unit and at leastone diol unit, the concentration of the double allylic structures of thevegetable oil in the composition may be greater than 5.0 meq/kg of allof the polyester components, and the composition may be substantiallyvoid of a polyamide.

It is further disclosed that the metal sulfonate salt group may be ametal sulfoisophthalate derived from a metal salt of 5-sulfoisophthalicacid, its dimethyl ester or its glycol ester. It is further disclosedthat the metal salt of 5-sulfoisophthalic acid, its dimethyl ester orits glycol ester may comprise a metal ion selected from the groupconsisting of Na⁺, Li⁺, K⁺, Zn²⁺, Mn²⁺, Co²⁺ and Ca²⁺. It is furtherdisclosed that the metal sulfonate salt group is preferably present in arange selected from the group consisting of 0.01 to 10.0 mole percent,0.01 to 2.0 mole percent, 0.05 to 1.1 mole percent, 0.10 to 0.74 molepercent and 0.10 to 0.6 mole percent based upon the total moles of acidunits in all of the polyester components.

It is further disclosed that the transition metal catalyst may be acompound containing at least one cobalt atom in a positive oxidationstate. It is further disclosed that the transition metal catalyst ispreferably a salt containing at least one cobalt atom in a positiveoxidation state. It is further disclosed that the transition metalcatalyst is preferably added to the composition at a level in a rangeselected from the group of between 10 and 600 ppm, between 20 and 400ppm and between 40 and 200 ppm of metal relative to the total amount ofthe polyester components and vegetable oil present in the composition.

It is further disclosed that the vegetable oil may be selected from thegroup consisting of flax seed oil, linseed oil, evening primrose oil,borage oil, sunflower oil, soybean oil, grapeseed oil, corn oil, cottonseed oil, rice bran oil, canola oil and peanut oil. It is furtherdisclosed that the composition may have a concentration of the doubleallylic structures of the vegetable oil in the composition is greaterthan 7.0 meq/kg of all of the polyester components. It is furtherdisclosed that the composition may have a concentration of the doubleallylic structures of the vegetable oil in the composition is greaterthan 9.0 meq/kg of all of the polyester components. It is furtherdisclosed that the composition may have a concentration of the doubleallylic structures of the vegetable oil in the composition is greaterthan 14.0 meq/kg of all of the polyester components.

It is further disclosed that the composition may be void of a polyamide.

It is further disclosed that the composition may further comprise TiO₂.It is further disclosed that the TiO₂ may be present in the compositionat a level in a range selected from the group consisting of between 0.1and 15% by weight of the composition, between 0.1 and 10% by weight ofthe composition, between 0.1 and 5% by weight of the composition andbetween 0.1 and 2% by weight of the composition.

Also disclosed herein is a preform manufactured from said compositions.Also disclosed herein is a biaxially oriented container manufacturedfrom said preform. Also disclosed herein is a film manufactured fromsaid compositions. Also disclosed herein is a sheet manufactured fromsaid compositions.

Also disclosed herein is an oxygen scavenging composition for containerswhich may comprise at least one polyester component, a transition metalcatalyst, a vegetable oil comprising at least one molecule having adouble allylic structure, and TiO₂, wherein the concentration of thedouble allylic structures of the vegetable oil in the composition may begreater than 5.0 meq/kg of all of the polyester components, and thecomposition may be substantially void of a polyamide.

It is further disclosed that the transition metal catalyst may be acompound containing at least one cobalt atom in a positive oxidationstate. It is further disclosed that the transition metal catalyst may bea salt containing at least one cobalt atom in a positive oxidationstate. It is further disclosed that the transition metal catalyst may beadded to the composition at a level in a range selected from the groupof between 10 and 600 ppm, between 20 and 400 ppm and between 40 and 200ppm of metal relative to the total amount of the polyester componentsand vegetable oil present in the composition.

It is further disclosed that the vegetable oil may be selected from thegroup consisting of flax seed oil, linseed oil, evening primrose oil,borage oil, sunflower oil, soybean oil, grapeseed oil, corn oil, cottonseed oil, rice bran oil, canola oil and peanut oil.

It is further disclosed that the concentration of the double allylicstructures of the vegetable oil in the composition may be greater than7.0 meq/kg of all of the polyester components. It is further disclosedthat the concentration of the double allylic structures of the vegetableoil in the composition may be greater than 9.0 meq/kg of all of thepolyester components. It is further disclosed that the concentration ofthe double allylic structures of the vegetable oil in the compositionmay be greater than 14.0 meq/kg of all of the polyester components.

It is further disclosed that the composition may be void of a polyamide.

It is further disclosed that the TiO₂ may be present in the compositionat a level in a range selected from the group consisting of between 0.1and 15% by weight of the composition, between 0.1 and 10% by weight ofthe composition, between 0.1 and 5% by weight of the composition andbetween 0.1 and 2% by weight of the composition.

Also disclosed herein is a preform manufactured from said compositions.Also disclosed herein is a biaxially oriented container manufacturedfrom said preform. Also disclosed herein is a film manufactured fromsaid compositions. Also disclosed herein is a sheet manufactured fromsaid compositions.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 is a graph of oxygen ingress data of the experimental runs 1through 6 reported herein.

DETAILED DESCRIPTION

The addition of a transition metal catalyst, specifically a cobaltcompound and more specifically a cobalt salt, to blends of polyestersand polyamides to create an active oxygen scavenging system with thepolyamide reacting with the oxygen is well known in the art. Theaddition of vegetable oils to polyester/polyamide compositions forpreforms and containers for initiating oxygen scavenging is also knownin the art, see for example U.S. Pat. No. 8,871,846 B2 to Fava (“Fava”).

Many vegetable oils are known to contain at least one molecule having adouble allylic structure. One type of double allylic structure is a monoDiallylic having the general structure:

Mono Diallylic structures are found in, for instance, linoleic acid,which is a common component of many vegetable oils. Another type ofdouble allylic structure is a bis Diallylic having the generalstructure:

Bis Diallylic structures are found in, for instance, linolenic acid,which is a common component of several vegetable oils. What theinventors have found is that the vegetable oil can be an oxygenscavenger in its own right when the concentration of vegetable oil inthe composition is above a critical threshold. The critical threshold isconsidered to be the level at which the vegetable oil is no longercompletely solubilized in the polymer. Without wishing to be bound byany theory, it is believed that, if all of the vegetable oil issolubilized in the host polymer, there are no reactive sites availablefor scavenging oxygen. However, if the vegetable oil is added at aconcentration such that not all of the vegetable oil is solubilized inthe polymer, the vegetable oil will form reactive domains in thecomposition. While the solubility of the vegetable oil in the polymerwill vary slightly depending on the type of vegetable oil used, ingeneral the inventors have found that oxygen scavenging occurs when thevegetable oil is present in the composition at a level selected from thegroup consisting of greater than 0.6% by weight relative to the totalweight of the polyester components, the transition metal catalyst andthe vegetable oil, greater than 0.5% by weight relative to the totalweight of the polyester components, the transition metal catalyst andthe vegetable oil, greater than 0.4% by weight relative to the totalweight of the polyester components, the transition metal catalyst andthe vegetable oil and greater than 0.3% by weight relative to the totalweight of the polyester components, the transition metal catalyst andthe vegetable oil. Thus, the composition results in a preform,container, sheet or film having active oxygen scavenging characteristicswhen substantially void of a polyamide.

Further, the inventors have found that the amount of time that thecomposition will scavenge oxygen is dependent upon the milliequivalentsper kilogram (meq/kg) of double allylic structures from the vegetableoil in the final composition. The milliequivalents per kilogram (meq/kg)of double allylic structures is determined by first calculating themmole/kg of molecules containing mono Diallylic structures and themmole/kg of molecules containing bis Diallylic structures in therespective vegetable oil. For example, where the vegetable oil contains15% by weight linoleic acid having a molecular weight of 280.45, themmole/kg of mono Diallylic structures in the vegetable oil is 534.85,

$\left( {{\left( \frac{15}{280.45} \right) \times 10}{{,000} = 534.85}} \right).$

Where the vegetable oil also contains 54% by weight linolenic acidhaving a molecular weight of 278.43, the mmole/kg of bis Diallylicstructures in the vegetable oil is 1,939.45,

$\left( {{\left( \frac{54}{278.43} \right) \times 10}{{,000} = {1,939.45}}} \right).$

Once the mmole/kg of mono Diallylic structures and bis Diallylicstructures in the vegetable oil is known, this value can be used tocalculate the meq/kg of double allylic structures in the vegetable oilby adding the mmole/kg of mono Diallylic structures to the mmole/kg ofbis Diallylic structures multiplied by two. The mmole/kg of bisDiallylic structures is multiplied by two to take into account the factthat the bis Diallylic structures contain two reactive sites. Forexample, a vegetable oil containing 15% by weight linoleic acid and 54%by weight linolenic acid contains 4,413.75 meq/kg of double allylicstructures, (534.85+(1,939.45×2)=4,413.75). Once the meq/kg of doubleallylic structures in the vegetable oil is known, this value can be usedto calculate the milliequivalents per kilogram of polyester componentsin the final composition by dividing this number by the weight of thepolyester components in the composition.

To ensure acceptable oxygen scavenging performance and longevity, it ispreferred that the vegetable oil have a concentration of double allylicstructures greater than 1000 meq/kg, greater than 1500 meq/kg, greaterthan 2000 meq/kg, or greater than 2300 meq/kg, where the concentrationis a measure of the milliequivalents of the double allylic structurerelative to the weight of the vegetable oil. Accordingly, this discoveryis to a composition for containers comprising at least one polyestercomponent which is a copolyester containing a metal sulfonate saltgroup, a transition metal catalyst, and a vegetable oil comprising atleast one molecule having a double allylic structure, wherein thecopolyester containing a metal sulfonate salt group comprises at leastone acid unit and at least one diol unit, the concentration of thedouble allylic structures of the vegetable oil in the composition isgreater than 5.0 meq/kg of all of the polyester components, greater than7.0 meq/kg of all of the polyester components, greater than 9.0 meq/kgof all of the polyester components, or greater than 14.0 meq/kg of allof the polyester components and the composition is void of a polyamideor substantially void of a polyamide.

As used herein and in the claims, void of a polyamide means that thereis no polyamide present in the composition. As used herein and in theclaims, substantially void of a polyamide means that only trace amountsof a polyamide, such as less than 0.05% by weight polyamide, are presentin the composition. One in the industry would not expect this amount ofpolyamide to have any impact on the oxygen barrier performance of theresulting composition. One might find this amount of polyamide whenusing a post-consumer, recycled polyester as at least a portion of thepolyester component in the composition.

Also disclosed in this specification is a preform made from thepolyester composition of at least one polyester component which is acopolyester containing a metal sulfonate salt group, a transition metalcatalyst, and a vegetable oil comprising at least one molecule having adouble allylic structure. As explained in detail herein, the metalsulfonate salt group has been found to dramatically increase the amountof oxygen scavenging of the vegetable oil.

The polyester component is a polyester formed by the reaction product ofat least one dicarboxylic acid or its ester derivative and at least onediol. One useful polyester is a polyester with more than 85% of its acidunits being derived from terephthalic acid.

One example of a polyester component is a copolyester containing a metalsulfonate salt group which can be prepared by polymerization procedureswell-known in the art. The copolyester containing a metal sulfonate saltgroup may be prepared by melt phase polymerization involving thereaction of at least one diol unit with at least one dicarboxylic acidor its corresponding ester (the at least one acid unit) and a metal saltof 5-sulfoisophthalic acid or its corresponding ester.

In general, the copolyester containing a metal sulfonate salt group maybe prepared, for example, by melt phase polymerization involving thereaction of at least one diol with at least one dicarboxylic acid or itscorresponding ester and a metal salt of 5-sulfoisophthalic acid or itscorresponding ester. Various copolymers resulting from use of multiplediols and dicarboxylic acids may also be used. Polymers containingrepeating units of only one chemical composition are homopolymers.Polymers with two or more chemically different repeat units in the samemacromolecule are termed copolymers. The diversity of the repeat unitsdepends on the number of different types of monomers present in theinitial polymerization reaction. In the case of polyesters, copolymersinclude reacting one or more diols with a diacid or multiple diacids,and are sometimes referred to as terpolymers. For example, apolyethylene terephthalate copolymer comprised of terephthalic acid,isophthalic acid and the lithium salt of 5-sulfoisophthalic acid is acopolyester.

Suitable dicarboxylic acids include those comprising from about 4 toabout 40 carbon atoms. Specific dicarboxylic acids include, but are notlimited to, terephthalic acid, isophthalic acid, naphthalene2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediaceticacid, diphenyl-4,4′-dicarboxylic acid, 1,3-phenylenedioxydiacetic acid,1,2-phenylenedioxydiacetic acid, 1,4-phenylenedioxydiacetic acid,succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid,furan-2,5-dicarboxylic acid and the like. Specific esters include, butare not limited to, phthalic esters and naphthalic diesters. A usefulpolyester is a polyester with more than 85% of its acid units beingderived from terephthalic acid.

These acids or esters may be reacted with an aliphatic diol preferablyhaving from about 2 to about 24 carbon atoms, a cycloaliphatic diolhaving from about 7 to about 24 carbon atoms, an aromatic diol havingfrom about 6 to about 24 carbon atoms, or a glycol ether having from 4to 24 carbon atoms. Suitable diols and glycol ethers include, but arenot limited to, ethylene glycol, 1,4-butanediol, trimethylene glycol,1,6-hexanediol, 1,4-cyclohexanedimethanol, diethylene glycol,resorcinol, 1,3-propanediol, neophenthyl glycol, isosorbide,2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) and hydroquinone.

Polyfunctional comonomers can also be used, typically in amounts of fromabout 0.01 to about 3 mole percent. Suitable comonomers include, but arenot limited to, trimellitic anhydride, trimethylolpropane, pyromelliticdianhydride (PMDA), and pentaerythritol. Polyester-forming polyacids orpolyols can also be used. Blends of polyesters and copolyesters may alsobe useful in the present invention.

It is also well known that di-ethylene glycol is formed in-situ in themanufacture of polyesters having ethylene glycol as their starting dioland that about 2 to 3 percent of the total moles of the final diol unitsin the polyester will be diethylene glycol. Therefore, the compositionmay have 97 mole percent of its diol units as ethylene glycol and 3 molepercent of its diol units as di-ethylene glycol.

The esterification or polycondensation reaction of the carboxylic acidsor their esters with the diol(s) typically takes place in the presenceof a catalyst. Suitable catalysts include, but are not limited to,antimony oxide, antimony triacetate, antimony ethylene glycolate,organomagnesium, tin oxide, titanium alkoxides, dibutyl tin dilaurate,and germanium oxide. These catalysts may be used in combination withzinc, manganese, or magnesium acetates or benzoates. Catalystscomprising antimony are preferred.

The metal sulfonate salt group is preferably a metal sulfoisophthalatederived from a metal salt of 5-sulfoisophthalic acid its dimethyl esteror its glycol ester. The metal salt of 5-sulfoisophthalic acid comprisesa metal ion selected from the group consisting of Na⁺, Li⁺, K⁺, Zn²⁺,Mn²⁺, Co²⁺, Ca²⁺ and the like. The copolyester containing the metalsulfonate salt group is made by copolymerizing the metal sulfonate intothe polymer chain.

The importance of the metal sulfonate salt can be seen in FIG. 1. Asshown in FIG. 1, compositions made without the metal sulfonate saltexhibited minimal oxygen scavenging and often times variable andunpredictable oxygen scavenging. Surprisingly, the presence of the metalsulfonate salt, even at very low levels, increased the oxygen scavengingperformance of the vegetable oil and eliminated most, if not all of thevariations and unpredictability.

One suitable copolyester containing a metal sulfonate salt group is acopolymer of polyethylene terephthalate (PET) modified with a metalsulfoisophthalate derived from the di-ester or di-carboxylic acid of ametal sulfoisophthalate in the approximately 1:1 stoichiometric reactionof acids, or their di-esters, with ethylene glycol. Specific copolymersand terpolymers also include crystallizable and non-crystallizablepolyesters comprising a metal sulfoisophthalate in combination withisophthalic acid or its diester, 2,6 naphthalate dicarboxylic acid orits diester, and/or cyclohexane dimethanol.

The amount of metal sulfonate salt group in the polyester component, inparticular, metal sulfoisophthalate (derived from a metal salt of5-sulfoisophthalic acid), is preferably in the range of about 0.01 to10.0 mole percent based on the total acid units in all of the polyestercomponents of the composition, with an optimal amount being in the rangeof about 0.01 to about 2.0 mole percent based on the total acid units inall of the polyester components of the composition, with the range ofabout 0.05 to about 1.1 mole percent based on the total acid units inall of the polyester components of the composition being more optimal,and about 0.10 to about 0.74 mole percent based on the total acid unitsin all of the polyester components of the composition being even betteryet, with the range of about 0.10 to about 0.6 mole percent based on thetotal acid units in all of the polyester components of the compositionbeing the most optimal range. The amount of metal sulfonate salt groupin the composition is calculated on the basis of the moles of the totalacid groups in all of the polyester components present in thecomposition.

One preferred metal sulfoisophthalate is derived from5-lithiumsulfoisophthalic acid. The molecular structure of5-lithiumsulfoisophthalic acid is:

5-Lithiumsulfoisophthalic Acid (LiSIPA) or Sulfonic Acid Lithium SaltModified Isophthalic Acid

As is evident from the above diagram, the 5-lithiumsulfoisophthalic acidis a lithium sulfonate and comprises lithium sulfoisophthalate. Thelithium sulfoisophthalate refers to the compound as it is appearsincorporated into the polymer chain. This is also known as the repeatingunit of 5-lithiumsulfoisophthalic acid. Lithium sulfoisophthalatetherefore is the 5-lithiumsulfoisophthalic acid less one water molecule,with one hydroxyl group removed from one of the carboxyl end groups anda hydrogen removed from the other carboxyl end group. This molecule isthen attached to one or more monomers (R₁ and R₂) in the polymerbackbone.

The metal sulfonate salt group, in this case lithium sulfoisophthalate,is the molecule between the two R groups. Again, R could be the samemonomer, in the case of PET, the R's are likely the same being theethylene glycol moiety as reacted into the polymer chain.

Typical levels of the metal sulfonate salt group in a polyester polymerrange from 0.01 mole percent to 15 mole percent with respect to thetotal number of moles of the respective acid unit. For example, atypical homopolymer polyester has 100 mole percent terephthalic acidunits and 100 mole percent glycol units (ethylene glycol and di-ethyleneglycol). A polyester containing 5 mole percent of a metal salt ofsulfoisophthalic acid co-monomer would be derived from 95 moles ofterephthalic acid, 5 moles of metal sulfonate (such as5-lithiumsulfoisophthalic acid) and 100 moles of ethylene glycol.Similarly, it may be advantageous to add another co-monomer such asisophthalic acid. For example, a 2 mole percent isophthalate polymerwould contain 93 moles terephthalic acid, 2 moles of isophthalic acid, 5moles of metal sulfonate (such as 5-lithiumsulfoisophthalic acid) and100 moles ethylene glycol to make 100 moles of the polymer repeat unit.

Examples of copolyesters containing a metal sulfonate salt groupemployed in the present invention are those prepared by virtually anypolycondensation polymerization procedure. The traditional techniquescan be divided into the ester, acid, and modified processes. In theester process, the dimethyl ester of the dicarboxylic acid or acids isreacted with the diol or diols in the presence of heat and the methanolremoved yielding the bis-hydroxyethyl ester of the acids. Thebis-hydroxyethyl ester is then polymerized in its liquid form bysubjecting the material to vacuum and heat to remove the glycols andincrease the molecular weight. A typical process for the object polymerwould start with these ratios: 98 moles of dimethyl terephthalate, 2moles of dimethyl lithium salt of sulfoisophthalate and 220 moles ofdiol, typically ethylene glycol. Of the 220 moles of diol, 120 areexcess which are removed during processing. It should be noted that itis possible to obtain the sulfonated co-monomer in either itsbis-(hydroxyethyl) or dimethyl ester form.

For clarification, the phrase copolymerized with at least X percent of aspecific acid means that the compound is considered as part of the acidgroup of the polymer, such as terephthalic or isophthalic acid. Itprovides the reference to determine how many moles of the compound touse. The phrase does not mean that the compound must be added to theprocess as an acid. For example, 5-lithiumsulfoisophthalic acid could becopolymerized into polyethylene terephthalate as the acid, with twocarboxylic end groups, the dimethyl ester of the carboxylic acid, or thebishydroxy ester of the dimethyl ester or even very low molecular weightoligomers of a glycol acid polymer where the acid units are at least inpart, the sulfoisophthalate salt.

The phrase “copolymerized salt of the acid” should not limit the claimto only using the acid form, but should be read to mean the compound isone of the acid groups in the polymer.

The phrase “copolymerized with” means that the compound has beenchemically reacted with the polymer, such as in the polymer chain or asa pendant group. For example, a polyester copolymerized with lithiumsulfoisophthalate, or modified by copolymerizing at least 0.01 molepercent 5-lithiumsulfoisophthalic acid into the polyester, means thatthe lithium sulfoisophthalate is bonded to the polymer, including boundinto the polymer chain, with at least one chemical bond. The phrases areindifferent to how the material is incorporated into the polymer. Apolyester copolymerized with lithium sulfoisophthalate, or modified bycopolymerizing at least 0.01 mole percent lithium sulfoisophthalate intothe polyester refers to a polyester containing the lithiumsulfoisophthalate whether that lithium sulfoisophthalate wasincorporated using but not limited to 5-lithiumsulfoisophthalic acid,lithium sulfobenzoic acid, the dimethyl ester of5-lithiumsulfoisophthalic acid, the methyl ester of lithium sulfobenzoicacid, the di-alcohol of lithium sulfoisophthalate, the lithiumsulfohydroxy benzene, the lithium salt of hydroxy benzene sulfonic acid,or oligomers or polymers containing the lithium sulfoisophthalate.

The phrases “and derivatives” and “and its derivatives” refer to thevarious functionalized forms of the metal sulfonate salt which can becopolymerized into the polymer. For example, lithium sulfoisophthalate“and its derivatives” refers collectively and is not limited to5-lithiumsulfoisophthalic acid, the dimethyl ester of5-lithiumsulfoisophthalic acid, the bis-hydroxyethyl ester of5-lithiumsulfoisophthalic acid, the di-alcohol of lithiumsulfoisophthalate, low molecular weight oligomers, and high I.V.polymers containing lithium sulfoisophthalate in the polymer chain.

The same nomenclature applies to the glycol or diol.

In the acid process, the starting materials are the dicarboxylic acids,with water being the primary by-product. The charge ratio in a typicalacid process is 98 moles terephthalic acid, 2 moles of a metal salt ofsulfoisophthalic acid (e.g. 5-lithiumsulfoisophthalic acid—LiSIPA), and120 moles of diols, typical ethylene glycol. After reaction of the diolswith the acids, the material is subjected to the same polymerizationprocess conditions as the ester process.

The modified processes are variations of either process: combining theintermediary product at certain steps. One example is to pre-polymerizethe raw materials without the metal salt of sulfoisophthalic acid to alow molecular weight. In the case of the examples described below, themolecular weight of the low molecular weight polyester was typically inthe range 0.096 to 0.103 dl/g (intrinsic viscosity), having a carboxylend group number ranging from 586 to 1740 equivalents per 1,000,000grams of polymer. The molecular weight could be easily varied withoutundue experimentation as it has been for many years by those of ordinaryskill in the art when optimizing the addition point for their additives.

Another example of a variation is to use the acid process with justterephthalic acid to produce its low molecular weight intermediate andthe ester process used to produce the bis-hydroxyethyl ester of thehomopolymer sulfonated polyester. These two intermediates are thencombined and polymerized to a copolymer. Another variation is to add thefinished modified polymer to the melt reactor and let the melt processdepolymerise the modified polymer and then form a copolymer.

The copolyesters of this invention may also contain small amounts ofphosphorous compounds, such as phosphates. Also, small amounts of otherpolymers such as polyolefins can be tolerated in the continuous matrix.

After completion of the melt phase polymerization, the polymer is eithermade into a form such as a film or part or stranded and cut into smallerchips, such as pellets. The polymer is usually then crystallized andsubjected to a solid phase (solid state) polymerization (SSP) step toachieve the intrinsic viscosity necessary for the manufacture of certainarticles such as bottles. The crystallization and polymerization can beperformed in a tumbler dryer reactor in a batch-type system. The solidphase polymerization can continue in the same tumble dryer where thepolymer is subjected to high vacuum to extract the polymerizationby-products.

Alternatively, the crystallization and polymerization can beaccomplished in a continuous solid state polymerization process wherebythe polymer flows from one vessel to another after its predeterminedtreatment in each vessel. The crystallization conditions are relative tothe polymer's crystallization and sticking tendencies. However,preferable temperatures are from about 100° C. to about 235° C. In thecase of crystallisable polyesters, the solid phase polymerizationconditions are generally 10° C. below the melt point of the polymer. Inthe case of non-crystallisable polyesters, the solid phasepolymerization temperature is generally about 10° C. below temperaturewhere the polymer begins sticking to itself. While traditional solidphase polymerization temperatures for crystallisable polymers range fromabout 200° C. to about 232° C., many operations are from about 215° C.to about 232° C. Those skilled in the art will realize that the optimumsolid phase polymerization temperature is polymer specific and dependsupon the type and amount of copolymers in the product. However,determination of the optimum solid phase polymerization conditions isfrequently done in industry and can be easily done without undueexperimentation.

The solid phase polymerization may be carried out for a time sufficientto raise the intrinsic viscosity to the desired level, which will dependupon the application. For a typical bottle application, the preferredintrinsic viscosity (I.V.) is from about 0.65 to about 1.0deciliter/gram, as determined by the method described in the methodssection. The time required to reach this I.V. from about 8 to about 21hours.

Vegetable oils of the present invention may be selected from the groupconsisting of flax seed oil, linseed oil, evening primrose oil, borageoil, sunflower oil, soybean oil, grapeseed oil, corn oil, cotton seedoil, rice bran oil, canola oil and peanut oil. Preferably the vegetableoil comprises at least one molecule having a double allylic structure.One type of double allylic structure is a mono Diallylic having thegeneral structure

Mono Diallylic structures are found in, for instance, linoleic acid,which is a common component of many vegetable oils. Another type ofdouble allylic structure is a bis Diallylic having the general structure

Bis Diallylic structures are found in, for instance, linolenic acid,which is a common component of several vegetable oils.

Examples of molecules having a double allylic structures found in manyvegetable oils include linoleic acid and gamma linolenic acid. Linoleicacid has the general structure of:

Gamma linolenic acid has the general structure of:

One especially preferred vegetable oil is flax seed oil. Flax seed oilis raw, cold pressed oil derived from the seed from the plant Linumusitatissimum. Flax seed oil is a poly-unsaturated ester having amixture of fatty acids, primarily in the form of triacylglycerides, witheach triacylglyceride comprised of three acids selected from the groupconsisting of triply saturated alpha-linolenic acid, saturated acidpalmitic acid, saturated acid stearic acid, monosaturated oleic acid,and doubly saturated linoleic acid. The poly-unsaturated ester of flaxseed oil has the general structure of:

and isomers thereof.

Flax seed oil is well known for having the alpha-linolenic acid as itslargest constituent. Flax seed oil is available as the cold pressed oil(known simply as flax seed oil) or as a chemically treated and heatedoil derived from the flax seed (known as linseed oil). The cold pressedflax seed oil is preferred over the chemically treated and heatedlinseed oil as it is generally regarded as safe for human consumption.

Vegetable oil is used as an oxygen scavenger in the compositionsdisclosed herein. Preferably, the vegetable oil is added at a level suchthat the concentration of double allylic structures of the vegetable oilin the composition is greater than 5.0 meq/kg of the total polyestercomponents, greater than 7.0 meq/kg of the total polyester components,greater than 9.0 meq/kg of the total polyester components, or greaterthan 14.0 meq/kg of the polyester components. The vegetable oil can beadded during the polymerization process of the copolyester containing ametal sulfonate salt group but is preferably added after thepolymerization process, such as at the extruder or during injectionmolding.

What has been found is that, when the vegetable oil is added to thecomposition at a level above a critical threshold, the vegetable oilwill act as an oxygen scavenger without the need for an additionaloxygen scavenging polymer, such as a polyamide.

In one embodiment, oxygen scavenging may be assisted by the use of atransition metal catalyst. One preferred transition metal catalyst is acompound containing at least one cobalt atom in a positive oxidationstate. A more preferred transition metal catalyst is a salt containingat least one cobalt atom in a positive oxidation state.

One preferred transition metal catalyst is a cobalt salt. Preferredcobalt salts include cobalt chloride, cobalt acetate, cobaltproprionate, cobalt stearate, cobalt octoate, cobalt neodecanoate,cobalt oleate, cobalt linoleate, cobalt salts of fatty acids, cobaltsalts of short chained fatty acids, cobalt salts of medium chained fattyacids, cobalt salts of long chained fatty acids, cobalt carbonate andcombinations thereof.

The preferred cobalt salt is an organic cobalt salt with the inorganiccobalt salts which can be solubilized in the polyester being lesspreferred.

The cobalt atom of the cobalt compound may also exist in the anion ofthe compound, such as lithium cobaltate (LiCoO₂) and potassiumtris(oxalto)cobaltate(III). The cobaltate may also be formed in situ bythe reaction of the cobalt atom in the presence of the polyester'scarboxylic acids in the presence of an alkali metal base.

The cobalt compound may also be a cobalt complex such as cobaltglycolate.

The transition metal catalyst is preferably in a range of between 10 and600 ppm of metal relative to the total amount of the polyestercomponents and vegetable oil present in the composition with a level inthe range of between 20 and 400 ppm relative to the total amount of thepolyester components and vegetable oil present in the composition beingmore preferred and a level in the range of between 40 and 200 ppmrelative to the total amount of the polyester components and vegetableoil present in the composition being most preferred.

The transition metal catalyst may be added during the polymerizationprocess of the copolyester containing a metal sulfonate salt group or itmay be added after the polymerization process, such as at the extruderor during injection molding.

In some embodiments, the polyester may be polymerized in the presence ofa phosphorous compound, such as polyphosphoric acid, phosphoric acid, ortriethyl phosphate, for example. When the polyester is polymerized inthe presence of a phosphorous compound, it is preferred to keep themolar ratio of the amount of moles of phosphorous to the moles of cobaltions in a range selected from the group consisting of 0 to 1.7, 0 to1.2, 0 to 1.1, 0 to 1.0, 0 to 0.8, and 0 to 0.6.

The components of the composition (the polyester component, thetransition metal catalyst and vegetable oil) are often melt blended inan injection molding extruder to make a film, sheet or preform. When thecomposition is injection molded to make a preform, the preform can thenbe biaxially stretched, such by reheat blow molding, to form a biaxiallyoriented container.

The compositions disclosed herein may include additional additivesincluding colorants, pigments, fillers, acid scavengers, processingaids, coupling agents, lubricants, stearates, blowing agents, polyhydricalcohols, nucleating agents, antioxidants, antistatic agents, UVabsorbers, slip agents, anti-fogging agents, anti-condensation agents,suspension stabilizers, anti-blocking agents, waxes and mixturesthereof. These additives are added at levels not inconsistent with theend use to make a commercially acceptable container. Generally, theseadditives are added at a level less than 5% by weight of thecomposition. For example, one preferred pigment is TiO₂ which, whenpresent, is preferably added to the composition at a level in a rangeselected from the group consisting of between 0.1 and 15% by weight ofthe composition, between 0.1 and 10% by weight of the composition,between 0.1 and 5% by weight of the composition and between 0.1 and 2%by weight of the composition.

EXAMPLES

The ability of a vegetable oil to scavenge oxygen in the absence of apolyamide was tested according to the following procedures. The PETresins (PET1, PET2, SIPA1) were dried (177° C., 5 hours, desiccated air)using a ConAir D175 Desiccant Carousel, then cooled and held at 135° C.in the dryer until injection molding. The experimental compositions forinjection molding were prepared by mixing the various PET/SIPA resinsand vegetable oils together in a metal can. Compositions comprising atleast one polyester component, a transition metal catalyst and avegetable oil were blended in an Arburg 420C injection molding extruderand molded into preforms. The compositions were injection molded into 28gram preforms having a 4 mm wall thickness. These preforms were thenblown into 500 mL bottles. Unless otherwise indicated, the materialsused in the experimental compositions include:

-   -   PET1=8006C-Co PET resin containing 102 ppm cobalt from cobalt        neodecanoate available from M&G Polymers USA, LLC, Apple        Grove, W. Va., USA    -   PET2=8006C PET resin available from M&G Polymers USA, LLC, Apple        Grove, W. Va., USA    -   SIPA1=Poliprotect SN resin comprising 0.33 mole % LiSIPA and        containing 138 ppm cobalt from cobalt neodecanoate available        from M&G Polymers USA, LLC, Apple Grove, W. Va., USA    -   Co=Cobalt Neodecanoate, 20.5% Co, Product No. 1354 available        from Shepherd Chemical, Norwood, Ohio, USA    -   FSO1=Conventional Grade Flax Oil available from TA Foods,        Yorkton, Saskatchewan, Canada    -   EPR=Bulk Evening Primrose Oil—Organic 9% GLA available from        Jedwards International, Braintree, Mass., USA    -   GSO=Bulk Grape Seed Oil—Virgin Organic available from Jedwards        International, Braintree, Mass., USA    -   SBO=Bulk Soybean Oil—Organic available from Jedwards        International, Braintree, Mass., USA    -   SFO=Bulk Sunflower Oil—Organic available from Jedwards        International, Braintree, Mass., USA        Unless otherwise indicated, the 28 g preforms were injection        molded using the following injection molding conditions:    -   IM1=Injection molded using an Arburg 420C injection molding        machine having a 30 mm diameter screw having a 23.1        length/diameter ratio rotating at 102 rpm. 525° F. (274° C.)        injection molding temperature, 2000 psi back pressure, 21 second        cycle per preform, 8 seconds of cooling in the mold subject to        32° F. (0° C.) chiller water.    -   IM2=Injection molded using an Arburg 420C injection molding        machine having a 30 mm diameter screw having a 23.1        length/diameter ratio screw rotating at 102 rpm. 540° F. (282°        C.) injection molding temperature, 2000 psi back pressure, 18        second cycle per preform, 5 seconds of cooling in the mold        subject to 41° F. (5° C.) chiller water.

Compositions comprising the components listed in Table 1 below weretested. In each run, the specific PET and SIPA components were blendedto achieve the reported final SIPA mole %. Runs 1 through 3 utilizedPET1 resin. Runs 4 through 6 utilized PET2 resin in combination withSIPA1 resin. The SIPA mole % reported in Table 1 is the measure of themoles of metal sulfonate salt group based upon the total moles of acidunits in all of the polyester components in the composition. The amountof cobalt reported in Table 1 is the measure of ppm cobalt from cobaltneodecanoate relative to the total amount of the polyester componentsand the vegetable oil present in the composition. The weight % of FSO1reported in Table 1 is the measure of the weight of flax seed oilrelative to the total weight of the polyester components, the transitionmetal catalyst (cobalt salt) and the flax seed oil. The double allylicconcentration reported in Table 1 is the milliequivalents of the doubleallylic structures in FSO1 relative to the total weight of the polyestercomponents (PET and SIPA) in kilograms.

TABLE 1 Double Allylic Vegetable Vegetable Concen- Injection Run SIPAOil Oil tration Co Molding No. (mol %) Type (wt %) (meq/kg) (ppm)Conditions 1 0.0  0.0   0.0 100 IM2 2 0.0  FSO1 0.75 32.3 100 IM1 3 0.0 FSO1 0.75 32.3 100 IM2 4 0.24 0.0   0.0 100 IM2 5 0.24 FSO1 0.75 32.3100 IM1 6 0.24 FSO1 0.75 32.3 100 IM2

After blowing the bottles, each bottle was tested for oxygen ingressusing a Fibox 4-Trace Fiber Optic Trace Oxygen Meter (ModelOxy-4-Trace-04-006) made by PreSens GmbH (www.presens.de, Regensburg,Germany). The meter reads a sensor dot which has been placed inside thesealed bottle. The principle of the sensor operation is based on thequenching of luminescence caused by the collision between molecularoxygen and luminescent dye molecules in the excited state. The sensordots and meter were calibrated according to the standards and proceduresgiven by the manufacturer. The amount of dissolved oxygen in the liquidsealed inside each bottle is calculated by the Fibox software.

In a continuously purged nitrogen box, freshly blow molded bottles areconditioned for 18 to 24 hours and then filled with 500 mL ofdeoxygenated water and carbonated by the addition of citric acid (5.54g) and sodium bicarbonate (95.81 g) to give the desired degree ofcarbonation (3.1 volumes of CO₂). The bottles have an overflow volume of534 mL. After filling, a transparent gas-tight plastic insert, which hasa Fibox sensor affixed to the interior top of the insert, is fitted intothe mount of each bottle. The top exterior of the plastic insert has athreaded hole for the attachment of the fiber optic coupler used to readthe Fibox sensor. The filled bottle with gas-tight insert is sealed witha metal retainer cap. The metal cap has an opening to permit reading ofthe Fibox sensor by the meter.

To take a reading, the bottles are shaken for 10 minutes (EberbachReciprocating Shaker, Model 6000) to ensure equilibration between theoxygen dissolved in the liquid and the oxygen in the bottle headspace.The fiber optic cable is attached to the top of the gas-tight plasticbottle insert. The meter reads the sensor dot and calculates thedissolved O₂ concentration while the bottle is gently shaken while lyingon its side.

An initial baseline oxygen reading is made on each newly filled bottle.The bottles are then aged under low light conditions in a roomcontrolled at 71.6±1° F. (22±0.5° C.) and 43±2% RH. The dissolved O₂concentration readings (ppm O₂ mg/L) are taken at regular time intervalsuntil the test is terminated. The change in dissolved ppm O₂ mg/L fromthe baseline (ΔO₂) for each run is reported below in Table 2 with agraph of the change in dissolved ppm O₂ mg/L reported in FIG. 1.

TABLE 2 Run 1 Run 2 Run 3 Run 4 Run 5 Run 6 Days (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂)(ΔO₂) (ΔO₂) 0 0.000 0.000 0.000 0.000 0.000 0.000 5 0.188 6 −0.004−0.002 7 0.188 0.005 11 0.293 12 0.458 14 0.394 0.015 −0.003 0.003 150.487 18 0.679 21 0.588 0.026 −0.001 0.003 22 0.675 27 1.062 28 0.7750.040 −0.004 −0.001 29 0.887 33 1.272 35 0.929 0.056 −0.004 0.000 361.013 40 1.503 42 1.030 0.073 −0.003 0.000 43 1.243 45 1.659 49 0.9480.097 0.000 0.001 50 1.419 55 0.002 0.006 56 0.958 0.125 57 1.728 602.090 63 1.084 0.156 0.007 0.006 64 1.827 70 1.190 0.192 0.014 0.009 712.058 77 1.351 0.239 0.009 0.011 83 1.502 84 0.286 0.022 0.018 91 1.6340.334 0.028 0.024 97 1.802 98 0.419 0.036 0.034 105 1.987 0.452 0.0460.045 111 2.148 112 0.517 0.059 0.060 119 0.569 0.077 0.080 125 0.636133 0.716 0.119 0.139 139 0.824 140 0.148 0.195 147 0.851 0.173 0.238153 0.956 168 0.298 0.431 174 1.174 175 0.359 0.500 181 1.274 182 0.4110.574 189 0.486 0.651 195 1.428 196 0.569 0.737 202 1.520 203 0.6560.837 209 1.564 210 0.752 0.920 216 1.612 217 0.899 1.103 223 1.677 2240.950 1.154 230 1.695 231 1.043 1.234 237 1.739 238 1.051 1.245 2441.800 245 1.202 1.422 251 1.843 252 1.310 1.500 258 1.901 *Cells withouta reported value represent days on which a dissolved oxygen reading wasnot taken for the run in question.The results reported in Table 2 above and visually displayed in FIG. 1show that the composition of at least one polyester which is acopolyester containing a metal sulfonate salt group, cobalt neodecanoateand vegetable oil scavenges oxygen (results in less O₂ ingress asindicated by the lower ΔO₂ at comparable reading times) irrespective ofcooling conditions and without the need for an additional polyamidecomponent.

Additional oxygen scavenging testing was performed using differentvegetable oils. The compositions used in these tests are summarizedbelow in Table 3. In each run, the specific PET and SIPA components wereblended to achieve the reported final SIPA mole %. Each run utilizedPET2 resin in combination with SIPA1 resin. The SIPA mole % reported inTable 3 is the measure of the moles of metal sulfonate salt group basedupon the total moles of acid units in all of the polyester components inthe composition. The amount of cobalt reported in Table 3 is the measureof ppm cobalt from cobalt neodecanoate relative to the total amount ofthe polyester components and the vegetable oil present in thecomposition. The weight % of the vegetable oil reported in Table 3 isthe measure of the weight of vegetable oil relative to the total weightof the polyester components, the transition metal catalyst (cobalt salt)and the vegetable oil. The double allylic concentration reported inTable 3 is the milliequivalents of the double allylic structures in thevegetable oil relative to the total weight of the polyester components(PET and SIPA) in kilograms

TABLE 3 Double Allylic Vegetable Vegetable Concen- Injection Run SIPAOil Oil tration Co Molding No. (mol %) Type (wt %) (meq/kg) (ppm)Conditions  7 0.24 EPR 0.40 13.2 100 IM2  8 0.24 EPR 0.50 16.5 100 IM2 9 0.24 EPR 0.75 24.8 100 IM2 10 0.24 GSO 0.40 10.7 100 IM2 11 0.24 GSO0.50 13.3 100 IM2 12 0.24 GSO 0.75 20.0 100 IM2 13 0.24 SBO 0.40  8.7100 IM2 14 0.24 SBO 0.50 10.9 100 IM2 15 0.24 SBO 0.75 16.3 100 IM2 160.24 SFO 0.30  6.2 100 IM2 17 0.24 SFO 0.50 10.3 100 IM2 18 0.24 SFO0.75 15.5 100 IM2

These compositions were tested for oxygen scavenging performance usingthe Fibox 4-Trace Fiber Optic Trace Oxygen Meter (ModelOxy-4-Trace-04-006) and the testing method described above. The resultsof these tests are reported below in Table 4.

TABLE 4 Evening Primrose Oil Grapeseed Oil Soybean Oil Sunflower Oil RunRun Run Run Run Run Run Run Run Run Run Run 7 8 9 10 11 12 13 14 15 1617 18 Days (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂) (ΔO₂)(ΔO₂) (ΔO₂) 0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.0000.000 0.000 0.000 5 0.101 0.030 -0.001 0.082 0.019 0.182 0.007 −0.009 70.003 0.182 0.060 8 0.010 11 −0.001 12 0.330 0.107 −0.002 0.301 0.090 130.401 0.069 −0.008 14 0.001 0.388 0.152 18 0.000 19 0.670 0.105 −0.01420 0.564 0.192 −0.005 0.503 0.137 21 0.000 0.598 0.255 25 0.001 26 0.9240.188 −0.014 27 0.780 0.312 −0.003 0.677 0.172 28 0.002 0.783 0.347 330.945 0.414 −0.004 0.814 0.190 −0.002 34 1.215 0.310 −0.017 36 0.0011.002 0.458 39 0.000 41 1.194 0.565 −0.005 1.006 0.223 42 0.003 1.1620.547

As can be seen in Table 4, each vegetable oil tested will not scavengeoxygen at a lower concentration in the composition (Runs 7, 10, 13 and16). However, when added at a higher concentration (Runs 8, 9, 11, 12,14, 15, 17 and 18) the vegetable oil will scavenge oxygen.

Additional experiments were conducted to determine the ability of acomposition containing a vegetable oil and TiO₂ to scavenge oxygen.Compositions comprising the components listed in Table 5 were tested.Both runs utilized PET1 resin as the polyester component. The amount ofcobalt reported in Table 5 is the measure of ppm cobalt from cobaltneodecanoate relative to the total amount of the polyester components,the vegetable oil and the TiO₂ present in the composition. The weight %of FSO1 reported in Table 5 is the measure of the weight of the flaxseed oil relative to the total weight of the polyester components, thetransition metal catalyst (cobalt salt) and the flax seed oil. Theweight % of TiO₂ reported in Table 5 is the measure of the weight ofTiO₂ relative to the weight of the entire composition. The TiO₂ wasintroduced into the composition as a masterbatch of 10% TiO₂ in PET. Thedouble allylic concentration reported in Table 5 is the milliequivalentsof the double allylic structures in FSO1 relative to the total weight ofthe polyester components in kilograms.

TABLE 5 Double Allylic Vegetable Vegetable Concen- Injection Run TiO₂Oil Oil tration Co Molding No. (wt %) Type (wt %) (meq/kg) (ppm)Conditions 19 1.0 0.0   0.0 90 IM2 20 1.0 FSO1 0.75 32.3 90 IM2

These compositions were tested for oxygen scavenging performance usingthe Fibox 4-Trace Fiber Optic Trace Oxygen Meter (ModelOxy-4-Trace-04-006) and the testing method described above. The resultsof these tests are reported below in Table 6.

TABLE 6 Days Run 19 (ΔO₂) Run 20 (ΔO₂) 0 0.000 0.000 6 0.196 −0.008 130.457 −0.014 23 0.653 −0.017 27 0.945 −0.018 34 1.132 −0.019 40 1.333−0.020

As can be seen in Table 6, the composition containing TiO₂ withoutvegetable oil does not scavenge oxygen while the composition with TiO₂and vegetable oil does scavenge oxygen as evidenced by the decreasedoxygen ingress after 40 days.

1-32. (canceled)
 33. An oxygen scavenging composition for containerscomprising: at least one polyester component which is a copolyestercontaining a metal sulfonate salt group, a transition metal catalyst,and a vegetable oil comprising at least one molecule having a doubleallylic structure, wherein the copolyester containing a metal sulfonatesalt group comprises at least one acid unit and at least one diol unit,the concentration of the double allylic structures of the vegetable oilin the composition is greater than 5.0 meq/kg of all of the polyestercomponents, and the composition is substantially void of a polyamide.34. The composition of claim 33, wherein the metal sulfonate salt groupis a metal sulfoisophthalate derived from a metal salt of5-sulfoisophthalic acid, its dimethyl ester or its glycol ester.
 35. Thecomposition of claim 34, wherein the metal salt of 5-sulfoisophthalicacid, its dimethyl ester or its glycol ester comprises a metal ionselected from the group consisting of Na⁺, Li⁺, K⁺, Zn²⁺, Mn²⁺, Co²⁺ andCa²⁺.
 36. The composition of claim 33, wherein the metal sulfonate saltgroup is in a range selected from the group consisting of 0.01 to 10.0mole percent, 0.01 to 2.0 mole percent, 0.05 to 1.1 mole percent, 0.10to 0.74 mole percent and 0.10 to 0.6 mole percent based upon the totalmoles of acid units in all of the polyester components.
 37. Thecomposition of claim 33, wherein the transition metal catalyst is acompound containing at least one cobalt atom in a positive oxidationstate.
 38. The composition of claim 33, wherein the transition metalcatalyst is a salt containing at least one cobalt atom in a positiveoxidation state.
 39. The composition of claim 33, wherein the transitionmetal catalyst is added to the composition at a level in a rangeselected from the group of between 10 and 600 ppm, between 20 and 400ppm and between 40 and 200 ppm of metal relative to the total amount ofthe polyester components and vegetable oil present in the composition.40. The composition of claim 33, wherein the composition is void of apolyamide.
 41. The composition of claim 33, wherein the compositionfurther comprises TiO₂.
 42. The composition of claim 41, wherein theTiO₂ is present in the composition at a level in a range selected fromthe group consisting of between 0.1 and 15% by weight of thecomposition, between 0.1 and 10% by weight of the composition, between0.1 and 5% by weight of the composition and between 0.1 and 2% by weightof the composition.
 43. A preform manufactured from the composition ofclaim
 33. 44. A biaxially oriented container manufactured from thepreform of claim
 43. 45. An oxygen scavenging composition for containerscomprising: at least one polyester component, a transition metalcatalyst, a vegetable oil comprising at least one molecule having adouble allylic structure, and TiO₂, wherein the concentration of thedouble allylic structures of the vegetable oil in the composition isgreater than 5.0 meq/kg of all of the polyester components, and thecomposition is substantially void of a polyamide.
 46. The composition ofclaim 45, wherein the transition metal catalyst is a compound containingat least one cobalt atom in a positive oxidation state.
 47. Thecomposition of claim 45, wherein the transition metal catalyst is a saltcontaining at least one cobalt atom in a positive oxidation state. 48.The composition of claim 45, wherein the transition metal catalyst isadded to the composition at a level in a range selected from the groupof between 10 and 600 ppm, between 20 and 400 ppm and between 40 and 200ppm of metal relative to the total amount of the polyester componentsand vegetable oil present in the composition.
 49. The composition ofclaim 45, wherein the composition is void of a polyamide.
 50. Thecomposition of claim 45, wherein the TiO₂ is present in the compositionat a level in a range selected from the group consisting of between 0.1and 15% by weight of the composition, between 0.1 and 10% by weight ofthe composition, between 0.1 and 5% by weight of the composition andbetween 0.1 and 2% by weight of the composition.
 51. A preformmanufactured from the composition of claim
 45. 52. A biaxially orientedcontainer manufactured from the preform of claim 51.